1. Field of the Invention
The present invention relates to an improvement in munitions, and in particular, the ignition systems for fixed and semi-fixed gun and cannon ammunition for enhancing the flame spread throughout the propellant charge.
2. Description of the Prior Art
Smaller calibers of artillery ammunition, known as fixed ammunition, are normally assembled as a compact unit. The unit includes a case that contains the propellant, a projectile or bullet attached to one end of the case, and a primer inserted in the other end. The case may be made of brass, steel or a plastic. The propellant is also known as smokeless powder or gunpowder.
Semifixed ammunition differs from fixed ammunition in that the projectile is separable from the case to permit an increase or decrease in the propellant charge to be made, thereby to effect an adjustment in the range.
The history of the development of ignition systems for fixed and semifixed gun and cannon ammunition shows a progression from percussion cap to percussion primer, from percussion primer to electric or percussion primer with a flash tube to a booster filled igniter flash tube affixed to an electric or percussion primer. Tank cannon ammunition cartridge cases usually incorporate an electric primer together with a booster propellant filled igniter flash tube located on the central axis of the cartridge case with blast vent holes located in rows (3 to 5) along the side or sides of the flash tube. This system has severe limitations when it is employed to ignite composite gun/cannon propellants, especially low vulnerability ammunition, (LOVA) propellants. A principal limitation is that of the quality of the propellant bed permeation by booster propellant flash. Uniformity is not easily obtained. Other disadvantages of ammunition cartridge cases utilizing flash tubes are flash tubes are expensive, they are difficult to assemble, and they are difficult to pack with the propellant charge with the flash tube in place. Thus, there is a need and a demand for a better propellant charge ignition booster for cased cartridge ammunition, a booster which in operation does not limit flash via vent holes in a flash tube.